Browsing by Subject "dental enamel"

Now showing 1 - 4 of 4
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    Fluoride dose-response of human and bovine enamel caries lesions under remineralizing conditions
    (2012-08) Lippert, Frank; Hara, Anderson T.; Department of Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    Purpose: To investigate the relative fluoride dose-response of human and bovine enamel caries lesions under remineralizing conditions and utilizing an established pH cycling model. Methods: Early caries-like lesions were formed in human and bovine enamel, characterized using Vickers surface microhardness (VHN) and assigned to five dentifrice treatment groups: 0/250/1100 ppm fluoride as sodium fluoride (F as NaF) formulation 1; 1100 ppm F as NaF formulation 2; 1000 ppm F as monofluorophosphate (MFP) formulation 3. The daily pH cycling regimen comprised: 4xl-minute dentifrice slurry treatments; lx4-hour acid challenge and intermittent remineralization in a l:l-mixture of pooled human/ artificial saliva. After 20 days, VHN of specimens were measured again and changes from lesion baseline calculated (REM). Subsequently, enamel fluoride uptake (EFU) was determined using the microdrill technique and specimens were demineralized again to determine their acid resistance (DEM). Data were analyzed using two-way ANOVA (factors: enamel, dentifrice). Results: Both enamel type and dentifrice as well as their interaction affected REM and DEM. EFU was only affected by dentifrice. Human and bovine enamel showed a good fluoride dose-response for REM and correlated well. However, bovine enamel showed more remineralization than human enamel. There were good correlations between dentifrice-F concentration vs. REM and EFU, and between REM vs. EFU, regardless of enamel type.
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    Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro
    (SciELO, 2023) Romero, Maria Jacinta Rosario; Bezerra, Sávio José Cardoso; Fried, Daniel; Lippert, Frank; Eckert, George Joseph; Hara, Anderson Takeo; Biomedical and Applied Sciences, School of Dentistry
    This study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p < 0.001) and m-EA group (D0 > D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p <0.001) but did not differ between moderate and no-EA (p = 0.25). Enamel surface loss with profilometry increased with severity (no-EA>m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions.
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    Supplementation of an Orange Juice with Dietary Proteins to Prevent Enamel and Dentin Erosion
    (2015-05) Ferreira, Stella S.; Scaramucci, Tais; Hara, Anderson T.; Aoki, Idalina V.; Sobral, Maria A. P.; Department of Preventive and Community Dentistry, IU School of Dentistry
    Protein supplementation may be an alternative to reduce the erosive potential of acidic drinks. The aim of this in vitro study was to evaluate the erosive potential of an orange juice modified by dietary proteins. A commercially available orange juice was added 0.2 g/L casein, 2.0 g/L ovalbumin and their combination. The juice with no additives and a commercially available calcium-modified juice were used as negative and positive controls, respectively. Human enamel and dentin specimens (n=11) were tested in an erosion-remineralization cycling model. Enamel was analyzed by surface microhardness and profilometry, whilst dentin by profilometry only. Statistical analyses were performed using one-way ANOVA followed by Tukey's test (p<0.05). Calcium-modified juice showed the lowest erosive potential for both analyses (p<0.05). For enamel, the protein-added groups did not differ from each other (p>0.05) and showed significantly lower enamel loss compared to negative control (p<0.05). Regarding surface microhardness, casein showed the highest values compared to negative control (p<0.05). For dentin, none of the protein-added groups showed lower values of surface loss compared to negative control (p>0.05). In conclusion, for enamel the protein-modified orange juices presented reduced erosion of enamel, with casein showing a trend for better protection. For dentin, no reduction in the erosive potential was observed for the tested protein-modified orange juices.
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    Susceptibility of fluorotic enamel to dental erosion-abrasion
    (SciELO, 2023) Silva, Cristiane Araújo Maia; de Sousa, Frederico Barbosa; Martinez-Mier, Esperanza Angeles; Kelly, Adam Benjamin; Eckert, George J.; Hara, Anderson Takeo; Biomedical and Applied Sciences, School of Dentistry
    Dental hard tissue conditions can be of pre- or post-eruptive nature, such as enamel fluorosis and erosive tooth wear (ETW), respectively. Dental enamel fluorosis is caused by the chronic and excessive intake of fluoride during enamel development, leading to increased fluoride concentration and increased porosity. ETW has become a common clinical condition and often impairs dental function and aesthetics. This in vitro study tested the hypothesis that fluorotic enamel presents different susceptibility to dental erosion-abrasion. It consisted of a 3×3×2 factorial design, considering a) fluorosis severity: sound (TF0), mild (TF1-2), moderate (TF3-4); b) abrasive challenge: low, medium, and high; and c) erosive challenge: yes or no. A total of 144 human teeth were selected according to the three fluorosis severity levels (n=48), and subdivided into six groups (n = 8) generated by the association of the different erosive and abrasive challenges. Enamel blocks (4×4 mm) were prepared from each tooth and their natural enamel surfaces subjected to an erosion-abrasion cycling model. After cycling, the depth of the lesions in enamel was assessed by profilometry. ANOVA showed that the three-way and two-way interactions among the factors were not significant (p > 0.20). Enamel fluorosis level (p=0.638) and abrasion level (p = 0.390) had no significant effect on lesion depth. Acid exposure caused significantly more enamel surface loss than water (p < 0.001). Considering the limitations of this in vitro study, fluorosis did not affect the susceptibility of enamel to dental erosion-abrasion.